1. Field of the Invention
The present invention relates generally to an endoscope apparatus and, more particularly, to a surgical instrument for the endoscope used for strip biopsy surgery.
2. Related Art
Generally, a small protruding lesion formed in the body cavity is resected by inserting a high-frequency resecting tool from a forceps channel of an endoscope, by fitting a incising loop made of a metal wire around the protruding lesion, and by applying a high frequency to the incising section. However, many small lesions do not involve a protuberance, making it impossible to fit the incising loop around the lesion.
For this reason, there has been recently developed so-called a strip biopsy surgery. In this operation, a physiological salt solution is poured into a non-protruding lesion through use of an endoscopic syringe, as disclosed in Japanese Utility Model No. Sho-51-53672, thereby causing the lesion to protrude beforehand. The incising loop of the high-frequency resecting tool is fit around the thus-protruded lesion, thereby incising the lesion at high frequencies.
Unexamined, published Japanese Patent Application No. Hei-5-212045 describes a surgical instrument for endoscopes having a sheath which permits the high-frequency resecting tool and the endoscopic syringe to move back and forth independently of each other. The surgical instrument of this type is not required to be inserted into or removed from the forceps channel for respective operations for pouring a physiological salt solution and for incising a lesion using high frequencies. As a result, the overall operations required by the strip biopsy can be simplified, and the efficiency of the operations can be improved.
FIGS. 5A and 5B are a perspective and a transverse cross-sectional views, respectively, showing the configuration of the distal end portion of the surgical instrument for endoscopes. As shown in FIGS. 5A and 5B, the surgical instrument 1 for endoscope is provided with a sheath 2 which is a flexible tube and has an external diameter to be fitted into the forceps channel of the endoscope. The sheath 2 is formed from an electrically insulating material.
The inside of the sheath 2 is partitioned by means of a partition wall 2c into two tubes 2a and 2b, each of which has a substantially semicircular cross section. The flexible tube 3 is inserted into the first tube 2a so that it moves back and forth by way of manual operations. A fluid injection needle 4 is fixed to a tip end of the tube 3, and a socket not shown which permits receipt of a syringe (e.g., a fluid supply member) is coupled to the handgrip end of the tube, thereby forming a syringe needle which permits injection of a physiological salt solution into the tissue of the body cavity.
The high-frequency resecting tool 5 is inserted into the second tube 2b so that it moves back and forth independently of the tube 3 by way of manual operations. A metal wire 6, which is widely bent at the front end thereof to form a loop, is attached to the high-frequency resecting tool 5. The loop-shaped part of the wire 6 performs as an incising section 7.
The wire 6, which is bent at its front end thereof, extends to the handgrip side of the surgical instrument for endoscope through the second 2b of the sheath 2, and can slidably moves back and forth therein by way of manual operations.
The operation of the surgical instrument 1 for endoscope having the foregoing configuration will now be described. First, the flexible tube 3 is inserted into the first tube 2a of the sheath 2, and the high-frequency resecting tool 5 is inserted into the second tube 2b. Further, the surgical instrument 1 for endoscope is inserted into the body cavity through manual operations by way of the forceps channel while the incising section 7 provided at the end of the resecting tool 5 and the fluid injection needle 4 secured to the distal end of the tube 3 are housed within the sheath 2.
While the leading end of the sheath 2 of the surgical instrument 1 for endoscope is guided to the vicinity of the lesion of tissue, the resecting section 7 is operated to protrude from the distal end of the sheath 2 through manual operations, so that the loop-shaped resecting section 7 comes to locate at the periphery of the lesion.
Under this condition, the tube 3 is forcefully pushed through manual operations, and the fluid injection needle 4 is stuck into the lesion. A physiological salt solution is poured into the lesion by means of the syringe. As a result of the foregoing operations, the lesion is protruded, and the thus-protruding lesion is inserted into the loop of the incising section 7, so that the protruding lesion is fitted into the incising section 7.
Next, the fluid injection needle 4 is retracted into the sheath 2 by manually pulling back the tube 3 and, thereafter, the incising section 7 is closed by manually retracting the wire 6 independently from the pulling-back operation of the tube 3, thereby tightly tying the lesion. Subsequently, a high frequency is applied to the wire 6 and the incising section 7 thereof from a high frequency power supply (not shown), thereby resecting the lesion.
In the conventional surgical instrument for endoscope, as described above, the fluid injection needle and the resecting tool are arranged to slide back and forth in the sheath independently of each other. At the time of a strip biopsy, a lesion must have been tied by means of the incising section of the resecting tool only after the fluid injection needle has been retracted into the sheath after a physiological salt solution has been poured into the lesion. In this way, the operator is required to perform retracting operations twice, thus deteriorating the operability of the surgical instrument for endoscope.